FM Broadcasting Chronology

This page shows some of the events in the early history of FM
broadcasting in the United States. Note that apex stations referred
to on this page used amplitude modulation on VHF frequencies; many of
them evolved into FM stations. For dates involving the earliest
stations, see also the "earliest FM stations" page at this website.
Thanks to Bob Carpenter, Winston Tharp, Donna Halper, Steve Reggie,
and Robert W. Paine, who assisted with this page. The page is
maintained by Jeff Miller.
Suggestions are welcome.

1902. A patent application submitted by Cornelius Ehret of Philadelphia describes the use of
frequency modulation in both radiotelegraphy and radiotelephony and includes circuitry for both
FM transmission and reception, according to Gary Frost in Early FM Radio: Incremental Technology in Twentieth-Century America.

1921. The term wave-length modulation appears in
Thermionic Tubes by J. Scott-Taggart.

Feb. 1922. A paper “Notes on the Theory of Modulation” by J.
R. Carson appearing in the Proceedings of the Institute of Radio
Engineers contains the earliest known use of the term frequency
modulation:

It has been proposed..to employ an apparently radically
different system of modulation which may be termed frequency
modulation as distinguished from amplitude modulation, in the belief
that the former system makes possible the transmission of signals by
a narrower range of transmitted frequencies.

The paper shows that
the bandwidth required for frequency modulation is at least twice the
highest modulating frequency. The paper concludes that “this method
of modulation inherently distorts without any compensating advantages
whatsoever.”

Nov. 5, 1935. Armstrong demonstrates reception of W2AG at a
meeting of the Institute of Radio Engineers 17 miles from the station.
The ID for the transmission was, “This is amateur station W2AG at
Yonkers, New York, operating on frequency modulation at two and a half
meters.”

June 1936. Armstrong describes his FM system at FCC hearings;
critics predict the system is impractical.

July 1936. Armstrong granted experimental license for FM
station.

Jan. 1, 1937.Broadcasting reports apex station W9XAZ
Milwaukee (Milwaukee Journal) has become, as far as is known, the
first apex station to originate its own programs on a regular
schedule. Station operates on 26.4 MHz.

Mar. 2, 1937. The FCC authorizes two new apex stations, to WCHS
Charleston WV, for the 26 MHz band, and to KGFJ Los Angeles, in the
88, 120, 240, and 500 MHz bands. These are the first apex
authorizations since Jan. 21, 1936.

Mar. 9, 1937. The FCC authorizes an apex station to General
Electric in Albany on 31.6 to 41.0 MHz.

Spring 1937. Shepard applies for a permit for a 50-kW FM
station in Paxton.

Jan. 27, 1938. FCC announces its allocation of 25 channels with
40 kHz separation from 41.02 to 41.98 for use by educational stations.
Stations are to use amplitude modulation unless a need for FM can be
shown.

Jan. 15, 1938.Broadcasting reports Yankee Network
starts construction of a 50 kw FM station atop Mt. Washington and that
Armstrong is building a 50 kw FM station at Alpine NJ.

Apr. 10, 1938. Edwin H. Armstrong's W2XMN carrier is turned on
for the first time, 43.7 MHz, 600 watts.
For more information on W2XMN, see the
E. H. Armstrong website.

Oct. 1938. Construction of W1XOJ begins.

Nov. 1938. WNYE New York goes on the air, using amplitude
modulation.

Nov. 21, 1938. WBOE Cleveland is licensed for 500 watts on 41.5
MHz, using amplitude modulation. According to the 1961-62
Broadcasting Yearbook, the station went on the air in Oct.
1938.

Late 1938. W1XER moves its transmitter from Quincy to Mount
Washington and begins operation on 42.3 MHz, using amplitude
modulation.

Jan. 11, 1939. FCC engineers listen to Armstrong's FM station
from Sayville, New Jersey, 50 miles from the transmitter site. The
station was operating on 42.8 MHz with 20 kw. They also listen to FM
station W2AG Yonkers, operating on 110 MHz with 500 watts.

Feb. 1, 1939.Broadcasting reports General Electric
engineers recently set up two experimental frequency modulation
transmitters at Albany and Schenectady, operating on the same
frequency. They drove a test car between the two cities and found
almost no areas of interference between the stations. The stations
were W2XDA Schenectady and W2XOY New Scotland.

Feb. 1, 1939.Broadcasting reports that the FCC feels
that tests using frequency modulation should be expedited before apex
broadcasters, using amplitude modulation, become entrenched. It
reports about a dozen apex stations are licensed, and that several are
receiving highly satisfactory results, notably WWJ, WKY, and WBEN.

Feb. 1, 1939.Broadcasting reports Professor Daniel
Noble of Connecticut State College is experimenting with FM in the 100
MHz band.

Mar. 23, 1939. Armstrong demonstrates reception of his 20 kw FM
transmitter at Alpine and a 600-watt transmitter at Yonkers to the
Radio Club of America at Columbia University.

April 1939. Apex station W4XA Nashville begins a regular
schedule of programs on 26.15 MHz.

May 26, 1939. John Shepard in conjunction with the Institute of
Radio Engineers demonstrates FM at Northeastern University for several
hundred college professors, engineers, scientists, and technicians.

May 27, 1939. W1XOJ Paxton (Yankee Network) goes on the air on
43.0 MHz with 2000 watts. (To relay programming the Boston studios of
the Yankee Network to Paxton, W1XOK on 133.03 MHz with 250 watts was
used. Donna Halper reports this station appears to have become WEOD
and then disappeared completely.)

June 1939. WTMJ applies for CP for experimental FM station

June 1, 1939.Broadcasting article lists stations using
Armstrong modulation now in operation or under construction:

July 18, 1939. First day of regular programming for W2XMN
Alpine (Armstrong), 42.8 MHz, 35,000 watts. The following is taken
from Rebel In Radio by Elliott M. Sanger:

On July 18, 1939, Armstrong's transmitter carried the
world's first regularly scheduled program on FM radio. The entire
program originated from WQXR's studios in New York City. The telephone
company had installed a special high-fidelity telephone line to carry
the program from the WQXR studios to W2XMN in Alpine, New Jersey. (The
first two selections were Tchaikovsky's "Haydn's Symphony No. 100" and
"Francesca da Rimini.”) Not too many people could listen, however, for
there were just 25 FM receivers in the world. But those who did listen
agreed that a revolution in radio broadcasting had taken
place.

July 24, 1939. W1XOJ Paxton begins a regular schedule of 16
hours a day on the air, on 43.0 MHz. The station is still using 2000
watts but later will increase to 50 kw.

Aug 1, 1939.Broadcasting reports there are four groups
of frequencies for FM:

in the C group are 26.3, 26.5, 26.7, 26.9

in the E group are 42.6 42.8 43.0 43.2 43.4

in the G group are 117.19 117.43 117.67 117.91

in the H group are any frequencies above 300 MHz except 400-401 MHz

Broadcasting also reports there are four stations
currently in operation with Armstrong modulation: Armstrong at
Alpine, General Electric at Schenectady, W1XPW Meriden (WDRC), and W1XOJ.
It reports construction permits have been issued to:

Paul Godley, consulting engineer, for a station at Alpine

C. M. Jansky, consulting engineer, for a station in Washington

John V. L. Hogan (WQXR) for a station at Long Island City

Westinghouse (WBZ-WBZA) for a station at Springfield

Head of the Lakes Broadcasting Co. (WEBC) for a station at
Duluth, Minn. (which currently operates apex station W9XJL, 250 watts,
which will be revamped for FM with 1000 watts on 26.3 MHz)

Sept. 1939. W3XO Washington is placed into operation, with 1000
watts on 43.2 MHz, according to Broadcasting of Nov. 1, 1939,
which reports Jansky & Bailey "are experimenting with it regularly.”

Oct. 15, 1939.Broadcasting reports WOR was recently
authorized an FM station on 43.3 MHz with 1000 watts, and that it will
use the call W2XWI.

Oct. 15, 1939. The abbreviation "F-M" makes its (apparent)
first appearance in Broadcasting magazine. Beginning with the
March 15, 1940, issue, the abbreviation is changed to "FM.”

Nov. 1, 1939.Broadcasting reports, "The Commission on
Oct. 24 also authorized W2XAG, F-M station at Yonkers, N. Y., operated
by Carman R. Runyon Jr., pioneer experimenter with the system, to
change to the high-frequency classification and to operate with 5,000
watts on 117.19 mc.”

Nov. 8, 1939. W2XQR New York (John V. L. Hogan) begins
broadcasting, on 43.2. The following is taken from Rebel In
Radio by Elliott M. Sanger:

The station had applied for an FCC license to broadcast
in the then new high fidelity FM band, and went on the air in November
1939, with call sign W2XQR - the first FM station in the world
(barring the experimental W2XMN of Armstrong). Major Armstrong lent
the station his FM transmitter which was promptly installed at 42nd
Street and Lexington Avenue, atop the 54 story Chanin Building. It
stayed there until the station moved to the Empire State building in
December 1965.

Dec. 3, 1939. Experimental FM relay broadcast is successful:
W2XCR Yonkers broadcast a special program which was picked up by W2XMN
Alpine, which relayed it to W2XPW Meriden. It was then received at the
WDRC studios.

Mar. 3, 1940.New York Times reports that with the
introduction this month of W2XOR, there are now three frequency
modulation stations in the area: W2XOR, on 43.4, with programs of the
Mutual Broadcasting System; W2XMN on 42.8, which is on the air Mondays
through Fridays from 4 to 11 p.m., with programs of the Columbia
Broadcasting System; and W2XQR on 43.4, which broadcasts daily from 5
to 10 p.m. [The article shows two stations on the same frequency;
this may be an error.]

Mar. 15, 1940.Broadcasting lists the status of FM
stations as of March 13.

May 20, 1940. FCC authorizes commercial FM effective July 1,
1940, on 42-50 MHz. However, the authorization is later rescinded.

June 15, 1940.Broadcasting reports educational stations
licensed to date for amplitude modulation are WBOE Cleveland and WNYE
New York, and that WBKY Beattyville, Ky., has a construction permit.
"It is presumed that these, along with all other future applicants,
will change to FM.”

June 15, 1940.Broadcasting reports W2XWG is operating
from 4 to 11 p.m. on Tuesdays through Saturdays on 42.6 MHz.

Sept. 4, 1940.Variety reports, "WDRC is divorcing
itself from its offspring FM station, W1XPW, putting same officially
on its own two feet Monday [as of September 16, 1940]. At that time,
W1XPW will become a separate entity, broadcasting its own programming
and maintaining its own staff. Believed to be the only FM in the
country to maintain its own set-up, it will operate at the start on a
12-hour a day basis.” The article also said that W1XPW had been "in
operation with 1000 watts power for about a year," and had applied to
the FCC for a boost to 50,000 watts [Donna Halper].

Dec. 8, 1940. The first advertising contract for FM broadcasts
was signed by the Longines Watch Company and provided for the
broadcasting of Longines time signals by W2XOR, New York, for 26 weeks
beginning January 1, 1941. [Dec. 8 is the date from Famous First
Facts; according to Broadcasting the date was Dec. 9.]

Dec. 18, 1940. W1XER Boston (Yankee Network) goes on the air as
an FM station with 1 kw, transmitting from Mount Washington, according
to Donna Halper. This station had previously been a 500-watt weather
bureau station (W1XOY), which John Shepard converted to his second FM
station.

Jan. 1, 1941. Commercial FM broadcasting is authorized to begin
on this date on 42 to 50 MHz (although five frequencies are reserved
for educational broadcasting).

Jan. 1, 1941.New York Times lists: 42.8 W2XMN; 43.5
W2XOR; 43.2 W2XQR

Jan. 14, 1941. W2XMN discontinues rebroadcasting programming
of CBS, which plans its own New York FM station. W2XMN arranges
a regular daily schedule of 10 hours of recorded music originating
from the Associated Recording Studios.

Jan. 15, 1941. W1XOJ increases power to 50,000 watts.

Feb. 1941. Non-commercial WBOE Cleveland OH becomes an FM
station.

Mar. 1, 1941. W47NV Nashville becomes the first station to be
licensed for commercial operation, on 44.7 MHz with 20 kw. This
station went off the air in 1951. [As stations are licensed for
commercial operation, their calls are changed to a new alphanumeric
system which indicates the frequency and location.]

Sept. 1, 1941. KALW broadcasts its first program,
"Schoolcast," after 30 days of experimentation, according to Mullany,
George G., "San Francisco Experiment in Radio Education,"
California Journal of Secondary Education, Oct. 1941, pp.
336-9.

Sept. 5, 1941. W75C Chicago (Moody Bible Institute) is authorized to operate on 47.5 MHz
with a power of 1000 watts, using a Western Electric 503-1 transmitter [according to a document with this date
seen by Bob Caithamer, Director of Engineering for Moody Broadcasting].

Feb. 1942.FM magazine reports, "K45LA, Los Angeles,
Don Lee station on 1,700-ft. Mt. Lee gets its programs over a 4-mile,
15,000-cycle line from the Hollywood Studios. Western Electric
transmitter puts 1 kw. into the Lingo antenna shown here. Power will
be increased later. Meanwhile, listeners from San Diego to Ventura
are becoming FM program enthusiasts. Station is programmed
independently, taking only high spots from Mutual and Don Lee nets.

Feb. 1942.FM magazine reports, "Metropolitan
Television, Inc., affiliated with Bloomingdale's department
store, has been granted an extension until June 30, 1942,
to complete construction of W75NY.”

Feb. 1942.FM magazine reports, "An FM CP has just been
issued to Amarillo Broadcasting Corporation for 45.1 mc. This
application has been pending for many months.”

Feb. 1942.FM magazine reports, "FM application of
American Network has been designated for a consolidated hearing
which will include seven applicants in the New York area.”

Feb. 1942.FM magazine reports, "W53PH, operated by
WFIL, put its full-power transmitter on the air February 10th. This
is a 10-kw. R. E. L. installation. FM studios are in the Widener
Building.

Feb. 1942.FM magazine reports, "Leonard Ash, president
of Capitol Broadcasting Company, Inc., has straightened us out on the
ST link situation. Yankee Network's link transmitter operating on
133.03 mc., was the first FM type to be installed. However,
Capitol's transmitter was the first to be put into commercial service
in the new 331 mc. band. It operates over an airline distance of 12
miles.”

Feb. 1942.FM magazine reports, "Zenith Radio
Corporation, operating W51C, has received a letter from a listener in
Monterey, Mexico, telling of daily reception of this station between
3:00 P. M. and 6:00 P. M. This is the greatest distance, 1,100
airline miles, from which consistent reception of the 50 kw.
transmitter has been reported.”

Mar. 1942.FM magazine reports, "The FM end of the GE
broadcasts are originating at W47NY, from which they are picked up on
W2XMN, and distributed on FM frequencies to W65H, and north to W43B
and W39B, to W2XOY and W47A, and to W53PH. The program is
transmitted on Tuesdays, Thursdays, and Saturdays at 6:30 to 6:45
p.m. on the FM stations, and at 6:00 to 6:15 P. M. on the 51 CBS
stations.”

Mar. 1942.FM magazine reports, "From this eminence at
500 Fifth Avenue, New York City, CBS is now maintaining a regular FM
program schedule. When the antenna is completed, the 3-kw. G. E.
transmitter will cover 12,000,000 listeners. Meanwhile, with a
temporary antenna, W67NY is putting out a splendid signal, and adding
greatly to the entertainment of listeners in the New York area.”

Mar. 1942. An article by Arnold Nygren, chief engineer of
WFIL-W53PH, Philadelphia, in FM magazine, reports that W53PH
is using a 10-kw REL type 520 DL transmitter and a 50-foot four-bay
Lingo antenna on top of a 250-foot tower on the roof of a 255 foot
building. The article also reported that beginning in January 1942
W53PH inaugurated a monthly program booklet, and that over 1,300
subscribers received the February booklet.

May 21, 1945. FCC announces allocation of spectrum above 25 MHz
with exception of 44-108 MHz but delays decision as to placement of FM
for propagation studies to be made by FCC and industry engineers. The
44-108 MHz spectrum is to be allocated, following tests, on one of the
following three alternatives:

Middle 1945. For a three month period in mid-1945, WMFM
programs were broadcast on both the regular 45.5 mc channel, and on an
experimental channel of 91 mc. with reception compared 80 mi away.
(Report submitted Sept. 1945)

Jan. 5, 1949. Armstrong obtains temporary restraining order
from Washington Circuit Court of Appeals allowing him to stay on 44.1
(brought as a result of July 1946 order eliminating lower FM band)

Apr. 29, 1952. The first multiplex broadcast during regular
programming by KE2XCC. A carrier of 25 kHz was used, with a frequency
swing of +/- 5 kHz.

Feb. 1, 1954. Edwin Armstrong dies

Mar. 6, 1954. KE2XCC goes off the air. At 7 p.m. the station
aired a program in memory of Armstrong; at 8:57 "This is the last
program of our 15 years of broadcasting"; Star-Spangled Banner; "As we
prepare to pull the switch and shut the station down, we salute the
memory of Edwin Howard Armstrong.”

Oct. 12, 1955. The first SCA grants are made to WPEN-FM in
Philadelphia and WWDC-FM in Washington.

June 5, 1961.Broadcasting reports that three stations announced they went on the air at
midnight May 31 in their respective time zones: WGFM Schenectady at midnight Eastern time,
WEFM Chicago at midnight Central time, and KMLA Los Angeles at midnight Pacific Daylight Saving Time.
It reported that the FCC granted type approval for stereo broadcasting at 2 p.m. May 31 to WGFM and WEFM.

(According to Dave Obergoenner, KCFM broadcast in stereo at the same moment as WEFM, using
a stereo generator designed and built by station Chief Engineer Ed Bench.
A history article in Radio World has: “At midnight on June 1, 1961, KCFM made history by
simultaneously signing on in stereo with two other FM stations in the
nation.” According to a web page, Bench received type approval on Jan. 2, 1961.)

1962. FCC revises FM rules, dividing the country into three
zones (instead of the previous two), creating class A, B, and C
stations, and adopting power limits for each class.